In a corn harvester there is provided an almost vertical panel which deflects towards an additional sieve located below the denser fraction of the undifferentiated vegetal threshing residuals thrown by the auxiliary beating cylinder in the direction of the discharge outlet. The additional sieve, by means of the air flow generated by the grain cleaning fan, selects the fraction of whole corncobs only. A transversal auger, provided with end paddles, collects the corncobs falling through the sieve and conveys them to a chipper device, wherein the knives-hold rotor together with the counter-knives wall form the inlet of the duct of a system for the pneumatic transport of chips into an additional container provided aboard. A pneumatic fan adjoining the chipper device sucks the corncob chips and ejects them out of the delivery mouth into the duct.
